code: def test_nan(self):
      x = pd.Series([np.nan, None, pd.NA, "", "This IS a STRING."])
      answers = [np.nan, np.nan, np.nan, 0, 3]
      self.compare(self.primitive(), x, answers)
  
file_path: featuretools/featuretools/tests/primitive_tests/natural_language_primitives_tests/test_whitespace_count.py
imports: import numpy
  import pandas
  from featuretools.primitives import WhitespaceCount
  from featuretools.tests.primitive_tests.utils import PrimitiveTestBase, find_applicable_primitives, valid_dfs
label_desc: Use image node_id 3 for calling the TestWhitespaceCount obj's underlying member method code with example usage: obj.test_nan() without return types